The invention relates to concerns a device for producing interweaving knots in a multi-filament thread as well as to a method for producing interweaving knots with such a device.
DE 41 40 469 A1 discloses a generic device for producing interweaving knots, as well as a generic method for producing interweaving knots in a multi-filament thread.
For the production of multi-filament threads, it is generally known that the individual filament strands in a thread are held together by so-called interweaving knots. Such interweaving knots are produced by treating the thread with compressed air. Depending on the type of thread and the process, the number of interweaving knots needed for each unit of length and the stability of the interweaving knots could be subject to different requirements. High knot stability and a high number of interweaving knots are needed for each unit of length in the thread especially in the production of carpet yarns, which are used immediately following a melt spinning process for further processing.
In order to achieve a relatively high number of interweaving knots when working with higher speeds of the thread, the generic device includes a rotating annular nozzle that interacts with a stationary stator. The annular nozzle includes a circumferential thread guiding groove, and at the base of said thread guiding groove, several radially aligned nozzle bores are evenly distributed about the circumference. The nozzle bores penetrate the annular nozzle from the guiding groove to an internal centering diameter, which is guided on the circumference of the stator. The stator comprises an internal pressure chamber which has a chamber opening that is connected to the circumference of the stator. The chamber opening on the stator, as well as the nozzle bores in the annular nozzle are located in a plane. As a result, the nozzle bores are fed one after another to the chamber opening when the annular nozzle is rotating. The pressure chamber is connected with a compressed air source to produce a pressure impulse in the thread guiding groove of the annular nozzle during the interaction of the nozzle bores and the pressure chamber opening. Opposite of the area of the mouth of the pressure chamber opening, a cover is provided at the annular nozzle which allows the yarn to be guided in a closed guiding groove. The inlet and outlet are formed, respectively, by an inlet thread guide and an outlet thread guide. For this purpose, the inlet thread guide and the outlet thread guide are arranged on the annular nozzle.
In the well-known device, the annular nozzle includes a plurality of nozzle bores evenly distributed about the circumference, thus producing a relatively high number of interweaving knots. However, it became apparent that the interweaving knots produced had relatively large dimensions and comparatively no stability. Such weakly developed interweaving knots are completely unsuitable especially for yarns that are immediately used for further processing.